/* -*- C++ -*-
 * Copyright 2019-2020 LibRaw LLC (info@libraw.org)
 *
 LibRaw uses code from dcraw.c -- Dave Coffin's raw photo decoder,
 dcraw.c is copyright 1997-2018 by Dave Coffin, dcoffin a cybercom o net.
 LibRaw do not use RESTRICTED code from dcraw.c

 LibRaw is free software; you can redistribute it and/or modify
 it under the terms of the one of two licenses as you choose:

1. GNU LESSER GENERAL PUBLIC LICENSE version 2.1
   (See file LICENSE.LGPL provided in LibRaw distribution archive for details).

2. COMMON DEVELOPMENT AND DISTRIBUTION LICENSE (CDDL) Version 1.0
   (See file LICENSE.CDDL provided in LibRaw distribution archive for details).

 */

#include "../../internal/dcraw_defs.h"

#define fcol(row, col) xtrans[(row + 6) % 6][(col + 6) % 6]
/*
   Frank Markesteijn's algorithm for Fuji X-Trans sensors
 */
void LibRaw::xtrans_interpolate(int passes)
{
  int c, d, f, g, h, i, v, ng, row, col, top, left, mrow, mcol;

  int cstat[4] = {0, 0, 0, 0};

  int val, ndir, pass, hm[8], avg[4], color[3][8];
  static const short orth[12] = {1, 0, 0, 1, -1, 0, 0, -1, 1, 0, 0, 1},
                     patt[2][16] = {{0, 1, 0, -1, 2, 0, -1, 0, 1, 1, 1, -1, 0,
                                     0, 0, 0},
                                    {0, 1, 0, -2, 1, 0, -2, 0, 1, 1, -2, -2, 1,
                                     -1, -1, 1}},
                     dir[4] = {1, LIBRAW_AHD_TILE, LIBRAW_AHD_TILE + 1,
                               LIBRAW_AHD_TILE - 1};
  short allhex[3][3][2][8], *hex;
  ushort min, max, sgrow, sgcol;
  ushort(*rgb)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE][3], (*rix)[3], (*pix)[4];
  short(*lab)[LIBRAW_AHD_TILE][3], (*lix)[3];
  float(*drv)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE], diff[6], tr;
  char(*homo)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE], *buffer;

  if (width < LIBRAW_AHD_TILE || height < LIBRAW_AHD_TILE)
    throw LIBRAW_EXCEPTION_IO_CORRUPT; // too small image
                                       /* Check against right pattern */
  for (row = 0; row < 6; row++)
    for (col = 0; col < 6; col++)
      cstat[fcol(row, col)]++;

  if (cstat[0] < 6 || cstat[0] > 10 || cstat[1] < 16 || cstat[1] > 24 ||
      cstat[2] < 6 || cstat[2] > 10 || cstat[3])
    throw LIBRAW_EXCEPTION_IO_CORRUPT;

  // Init allhex table to unreasonable values
  for (int i = 0; i < 3; i++)
    for (int j = 0; j < 3; j++)
      for (int k = 0; k < 2; k++)
        for (int l = 0; l < 8; l++)
          allhex[i][j][k][l] = 32700;

  cielab(0, 0);
  ndir = 4 << (passes > 1);
  buffer = (char *)malloc(LIBRAW_AHD_TILE * LIBRAW_AHD_TILE * (ndir * 11 + 6));
  merror(buffer, "xtrans_interpolate()");
  rgb = (ushort(*)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE][3])buffer;
  lab = (short(*)[LIBRAW_AHD_TILE][3])(
      buffer + LIBRAW_AHD_TILE * LIBRAW_AHD_TILE * (ndir * 6));
  drv = (float(*)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE])(
      buffer + LIBRAW_AHD_TILE * LIBRAW_AHD_TILE * (ndir * 6 + 6));
  homo = (char(*)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE])(
      buffer + LIBRAW_AHD_TILE * LIBRAW_AHD_TILE * (ndir * 10 + 6));

  int minv = 0, maxv = 0, minh = 0, maxh = 0;
  /* Map a green hexagon around each non-green pixel and vice versa:	*/
  for (row = 0; row < 3; row++)
    for (col = 0; col < 3; col++)
      for (ng = d = 0; d < 10; d += 2)
      {
        g = fcol(row, col) == 1;
        if (fcol(row + orth[d], col + orth[d + 2]) == 1)
          ng = 0;
        else
          ng++;
        if (ng == 4)
        {
          sgrow = row;
          sgcol = col;
        }
        if (ng == g + 1)
          FORC(8)
          {
            v = orth[d] * patt[g][c * 2] + orth[d + 1] * patt[g][c * 2 + 1];
            h = orth[d + 2] * patt[g][c * 2] + orth[d + 3] * patt[g][c * 2 + 1];
            minv = MIN(v, minv);
            maxv = MAX(v, maxv);
            minh = MIN(v, minh);
            maxh = MAX(v, maxh);
            allhex[row][col][0][c ^ (g * 2 & d)] = h + v * width;
            allhex[row][col][1][c ^ (g * 2 & d)] = h + v * LIBRAW_AHD_TILE;
          }
      }

  // Check allhex table initialization
  for (int i = 0; i < 3; i++)
    for (int j = 0; j < 3; j++)
      for (int k = 0; k < 2; k++)
        for (int l = 0; l < 8; l++)
          if (allhex[i][j][k][l] > maxh + maxv * width + 1 ||
              allhex[i][j][k][l] < minh + minv * width - 1)
            throw LIBRAW_EXCEPTION_IO_CORRUPT;
  int retrycount = 0;

  /* Set green1 and green3 to the minimum and maximum allowed values:	*/
  for (row = 2; row < height - 2; row++)
    for (min = ~(max = 0), col = 2; col < width - 2; col++)
    {
      if (fcol(row, col) == 1 && (min = ~(max = 0)))
        continue;
      pix = image + row * width + col;
      hex = allhex[row % 3][col % 3][0];
      if (!max)
        FORC(6)
        {
          val = pix[hex[c]][1];
          if (min > val)
            min = val;
          if (max < val)
            max = val;
        }
      pix[0][1] = min;
      pix[0][3] = max;
      switch ((row - sgrow) % 3)
      {
      case 1:
        if (row < height - 3)
        {
          row++;
          col--;
        }
        break;
      case 2:
        if ((min = ~(max = 0)) && (col += 2) < width - 3 && row > 2)
        {
          row--;
          if (retrycount++ > width * height)
            throw LIBRAW_EXCEPTION_IO_CORRUPT;
        }
      }
    }

  for (top = 3; top < height - 19; top += LIBRAW_AHD_TILE - 16)
    for (left = 3; left < width - 19; left += LIBRAW_AHD_TILE - 16)
    {
      mrow = MIN(top + LIBRAW_AHD_TILE, height - 3);
      mcol = MIN(left + LIBRAW_AHD_TILE, width - 3);
      for (row = top; row < mrow; row++)
        for (col = left; col < mcol; col++)
          memcpy(rgb[0][row - top][col - left], image[row * width + col], 6);
      FORC3 memcpy(rgb[c + 1], rgb[0], sizeof *rgb);

      /* Interpolate green horizontally, vertically, and along both diagonals:
       */
      for (row = top; row < mrow; row++)
        for (col = left; col < mcol; col++)
        {
          if ((f = fcol(row, col)) == 1)
            continue;
          pix = image + row * width + col;
          hex = allhex[row % 3][col % 3][0];
          color[1][0] = 174 * (pix[hex[1]][1] + pix[hex[0]][1]) -
                        46 * (pix[2 * hex[1]][1] + pix[2 * hex[0]][1]);
          color[1][1] = 223 * pix[hex[3]][1] + pix[hex[2]][1] * 33 +
                        92 * (pix[0][f] - pix[-hex[2]][f]);
          FORC(2)
          color[1][2 + c] = 164 * pix[hex[4 + c]][1] +
                            92 * pix[-2 * hex[4 + c]][1] +
                            33 * (2 * pix[0][f] - pix[3 * hex[4 + c]][f] -
                                  pix[-3 * hex[4 + c]][f]);
          FORC4 rgb[c ^ !((row - sgrow) % 3)][row - top][col - left][1] =
              LIM(color[1][c] >> 8, pix[0][1], pix[0][3]);
        }

      for (pass = 0; pass < passes; pass++)
      {
        if (pass == 1)
          memcpy(rgb += 4, buffer, 4 * sizeof *rgb);

        /* Recalculate green from interpolated values of closer pixels:	*/
        if (pass)
        {
          for (row = top + 2; row < mrow - 2; row++)
            for (col = left + 2; col < mcol - 2; col++)
            {
              if ((f = fcol(row, col)) == 1)
                continue;
              pix = image + row * width + col;
              hex = allhex[row % 3][col % 3][1];
              for (d = 3; d < 6; d++)
              {
                rix =
                    &rgb[(d - 2) ^ !((row - sgrow) % 3)][row - top][col - left];
                val = rix[-2 * hex[d]][1] + 2 * rix[hex[d]][1] -
                      rix[-2 * hex[d]][f] - 2 * rix[hex[d]][f] + 3 * rix[0][f];
                rix[0][1] = LIM(val / 3, pix[0][1], pix[0][3]);
              }
            }
        }

        /* Interpolate red and blue values for solitary green pixels:	*/
        for (row = (top - sgrow + 4) / 3 * 3 + sgrow; row < mrow - 2; row += 3)
          for (col = (left - sgcol + 4) / 3 * 3 + sgcol; col < mcol - 2;
               col += 3)
          {
            rix = &rgb[0][row - top][col - left];
            h = fcol(row, col + 1);
            memset(diff, 0, sizeof diff);
            for (i = 1, d = 0; d < 6; d++, i ^= LIBRAW_AHD_TILE ^ 1, h ^= 2)
            {
              for (c = 0; c < 2; c++, h ^= 2)
              {
                g = 2 * rix[0][1] - rix[i << c][1] - rix[-i << c][1];
                color[h][d] = g + rix[i << c][h] + rix[-i << c][h];
                if (d > 1)
                  diff[d] += SQR(rix[i << c][1] - rix[-i << c][1] -
                                 rix[i << c][h] + rix[-i << c][h]) +
                             SQR(g);
              }
              if (d > 1 && (d & 1))
                if (diff[d - 1] < diff[d])
                  FORC(2) color[c * 2][d] = color[c * 2][d - 1];
              if (d < 2 || (d & 1))
              {
                FORC(2) rix[0][c * 2] = CLIP(color[c * 2][d] / 2);
                rix += LIBRAW_AHD_TILE * LIBRAW_AHD_TILE;
              }
            }
          }

        /* Interpolate red for blue pixels and vice versa:		*/
        for (row = top + 3; row < mrow - 3; row++)
          for (col = left + 3; col < mcol - 3; col++)
          {
            if ((f = 2 - fcol(row, col)) == 1)
              continue;
            rix = &rgb[0][row - top][col - left];
            c = (row - sgrow) % 3 ? LIBRAW_AHD_TILE : 1;
            h = 3 * (c ^ LIBRAW_AHD_TILE ^ 1);
            for (d = 0; d < 4; d++, rix += LIBRAW_AHD_TILE * LIBRAW_AHD_TILE)
            {
              i = d > 1 || ((d ^ c) & 1) ||
                          ((ABS(rix[0][1] - rix[c][1]) +
                            ABS(rix[0][1] - rix[-c][1])) <
                           2 * (ABS(rix[0][1] - rix[h][1]) +
                                ABS(rix[0][1] - rix[-h][1])))
                      ? c
                      : h;
              rix[0][f] = CLIP((rix[i][f] + rix[-i][f] + 2 * rix[0][1] -
                                rix[i][1] - rix[-i][1]) /
                               2);
            }
          }

        /* Fill in red and blue for 2x2 blocks of green:		*/
        for (row = top + 2; row < mrow - 2; row++)
          if ((row - sgrow) % 3)
            for (col = left + 2; col < mcol - 2; col++)
              if ((col - sgcol) % 3)
              {
                rix = &rgb[0][row - top][col - left];
                hex = allhex[row % 3][col % 3][1];
                for (d = 0; d < ndir;
                     d += 2, rix += LIBRAW_AHD_TILE * LIBRAW_AHD_TILE)
                  if (hex[d] + hex[d + 1])
                  {
                    g = 3 * rix[0][1] - 2 * rix[hex[d]][1] - rix[hex[d + 1]][1];
                    for (c = 0; c < 4; c += 2)
                      rix[0][c] = CLIP(
                          (g + 2 * rix[hex[d]][c] + rix[hex[d + 1]][c]) / 3);
                  }
                  else
                  {
                    g = 2 * rix[0][1] - rix[hex[d]][1] - rix[hex[d + 1]][1];
                    for (c = 0; c < 4; c += 2)
                      rix[0][c] =
                          CLIP((g + rix[hex[d]][c] + rix[hex[d + 1]][c]) / 2);
                  }
              }
      }
      rgb = (ushort(*)[LIBRAW_AHD_TILE][LIBRAW_AHD_TILE][3])buffer;
      mrow -= top;
      mcol -= left;

      /* Convert to CIELab and differentiate in all directions:	*/
      for (d = 0; d < ndir; d++)
      {
        for (row = 2; row < mrow - 2; row++)
          for (col = 2; col < mcol - 2; col++)
            cielab(rgb[d][row][col], lab[row][col]);
        for (f = dir[d & 3], row = 3; row < mrow - 3; row++)
          for (col = 3; col < mcol - 3; col++)
          {
            lix = &lab[row][col];
            g = 2 * lix[0][0] - lix[f][0] - lix[-f][0];
            drv[d][row][col] =
                SQR(g) +
                SQR((2 * lix[0][1] - lix[f][1] - lix[-f][1] + g * 500 / 232)) +
                SQR((2 * lix[0][2] - lix[f][2] - lix[-f][2] - g * 500 / 580));
          }
      }

      /* Build homogeneity maps from the derivatives:			*/
      memset(homo, 0, ndir * LIBRAW_AHD_TILE * LIBRAW_AHD_TILE);
      for (row = 4; row < mrow - 4; row++)
        for (col = 4; col < mcol - 4; col++)
        {
          for (tr = FLT_MAX, d = 0; d < ndir; d++)
            if (tr > drv[d][row][col])
              tr = drv[d][row][col];
          tr *= 8;
          for (d = 0; d < ndir; d++)
            for (v = -1; v <= 1; v++)
              for (h = -1; h <= 1; h++)
                if (drv[d][row + v][col + h] <= tr)
                  homo[d][row][col]++;
        }

      /* Average the most homogenous pixels for the final result:	*/
      if (height - top < LIBRAW_AHD_TILE + 4)
        mrow = height - top + 2;
      if (width - left < LIBRAW_AHD_TILE + 4)
        mcol = width - left + 2;
      for (row = MIN(top, 8); row < mrow - 8; row++)
        for (col = MIN(left, 8); col < mcol - 8; col++)
        {
          for (d = 0; d < ndir; d++)
            for (hm[d] = 0, v = -2; v <= 2; v++)
              for (h = -2; h <= 2; h++)
                hm[d] += homo[d][row + v][col + h];
          for (d = 0; d < ndir - 4; d++)
            if (hm[d] < hm[d + 4])
              hm[d] = 0;
            else if (hm[d] > hm[d + 4])
              hm[d + 4] = 0;
          for (max = hm[0], d = 1; d < ndir; d++)
            if (max < hm[d])
              max = hm[d];
          max -= max >> 3;
          memset(avg, 0, sizeof avg);
          for (d = 0; d < ndir; d++)
            if (hm[d] >= max)
            {
              FORC3 avg[c] += rgb[d][row][col][c];
              avg[3]++;
            }
          FORC3 image[(row + top) * width + col + left][c] = avg[c] / avg[3];
        }
    }
  free(buffer);
  border_interpolate(8);
}
#undef fcol
